:: (Applicative m, Foldable f, Monoid b) => (a -> m b) -> f a -> m b is:exact

foldMapM :: (Applicative m, Foldable t, Monoid b) => (a -> m b) -> t a -> m b

Monadic version of foldMap

mapM' :: (Foldable t, Applicative m, Monoid b) => (a -> m b) -> t a -> m b

Generalized version of traverse_ :: Applicative m => (a -> m ()) -> [a] -> m () Executes effects and collects results in left-to-right order. Works best with left-associative monoids. Note that there is an alternative

mapM' f t = foldr mappend mempty $ mapM f t

that collects results in right-to-left order (effects still left-to-right). It might be preferable for right associative monoids.

foldMapA :: (Foldable t, Applicative f, Monoid m) => (a -> f m) -> t a -> f m

fmlist Data.FMList

Map each element of a structure to an action, evaluate these actions from left to right, and concat the monoid results.

foldMapM :: (Monoid b, Monad m, Foldable f) => (a -> m b) -> f a -> m b

relude Relude.Foldable.Fold

Polymorphic version of the concatMapM function.

>>> foldMapM @[Int] (Just . replicate 3) [1..3]
Just [1,1,1,2,2,2,3,3,3]

foldMapM :: (Monad m, Monoid w, Foldable t) => (a -> m w) -> t a -> m w

rio RIO.Prelude

Extend foldMap to allow side effects. Internally, this is implemented using a strict left fold. This is used for performance reasons. It also necessitates that this function has a Monad constraint and not just an Applicative constraint. For more information, see https://github.com/commercialhaskell/rio/pull/99#issuecomment-394179757.

foldMapA :: (Semigroup b, Monoid b, Applicative m, Foldable f) => (a -> m b) -> f a -> m b

relude Relude.Foldable.Fold

Polymorphic version of the concatMapA function.

>>> foldMapA @[Int] (Just . replicate 3) [1..3]
Just [1,1,1,2,2,2,3,3,3]

forM' :: (Foldable t, Applicative m, Monoid b) => t a -> (a -> m b) -> m b

Agda Agda.Utils.Monad

Generalized version of for_ :: Applicative m => [a] -> (a -> m ()) -> m ()